Dilution of total CK activity to 300 IU/L before isoenzyme separation will minimize the chance of detecting CK-MB positivity from a skeletal source. Our point is that transient elevations of CK-MB in serum, as has been reported after injury to drivers in automobile accidents,1 may be nonspecific rather than reflect myocardial damage. We agree that dilution may adversely affect CK-MB sensitivity for myocardial injury, but this is a limitation inherent in the technique.
Siegel AJ, Dawson DM. MB Fraction of Creatine Kinase-Reply. JAMA. 1981;245(23):2394. doi:10.1001/jama.1981.03310480013010